U.S. patent number 4,325,296 [Application Number 06/073,272] was granted by the patent office on 1982-04-20 for apparatus for adjusting internal pressure of aseptic storage tank.
This patent grant is currently assigned to Kagome Co., Ltd.. Invention is credited to Akira Funado, Nobuo Ukai, Tethuya Yokota.
United States Patent |
4,325,296 |
Ukai , et al. |
April 20, 1982 |
Apparatus for adjusting internal pressure of aseptic storage
tank
Abstract
A method and apparatus for supplying and maintaining an aseptic
gas atmosphere in a storage tank for spoilable contents such as
foodstuffs and the like. The aseptic gas is supplied from a
container under pressure and is maintained at the desired pressure
in the storage tank by pressure-reducing valves in a supply line or
conduit having a microbiological filter and pressure-maintaining
valve that functions in place of a relief valve in the supply line.
It responds to excess pressure in the storage tank and relieves the
excess pressure through the same supply line through which gas is
supplied without need of a relief valve on the storage tank.
Inventors: |
Ukai; Nobuo (Machida,
JP), Funado; Akira (Funabashi, JP), Yokota;
Tethuya (Mathudo, JP) |
Assignee: |
Kagome Co., Ltd. (Aichi,
JP)
|
Family
ID: |
14741127 |
Appl.
No.: |
06/073,272 |
Filed: |
September 7, 1979 |
Foreign Application Priority Data
|
|
|
|
|
Sep 28, 1978 [JP] |
|
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53-118624 |
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Current U.S.
Class: |
99/468; 422/28;
426/418; 99/471; 99/474; 99/483; 99/516 |
Current CPC
Class: |
A23B
7/152 (20130101); A23B 7/144 (20130101) |
Current International
Class: |
A23B
7/144 (20060101); A23B 7/152 (20060101); A23B
007/00 () |
Field of
Search: |
;99/471,468,473,474,483,484,516,536,467 ;426/615,418,521
;422/28 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Coe; Philip R.
Assistant Examiner: Simone; Timothy F.
Attorney, Agent or Firm: Burns; Robert E. Lobato; Emmanuel
J. Adams; Bruce L.
Claims
What we claim is:
1. Apparatus for maintaining an aseptic gaseous atmosphere in a
storage tank for spoilable foodstuffs and the like comprising, a
system connectable externally of said storage tank and having means
for providing a gas flow path for connecting a container of an
inert aseptic gas under pressure for supply of said gas to said
storage tank to supply an atmosphere of said gas in said storage
tank comprising adjustable pressure-reducing valve means
connectable in said same flow path to said gas container for
receiving said gas and reducing it to a given pressure level to be
maintained in the storage tank, a one-way valve connected in the
system in said same flow path downstream of said pressure-reducing
valve means to allow flow of said gas along a flow path in a
direction toward said storage tank only, means in said system for
connecting the one-way valve in said flow path to said tank, a
single pressure-maintaining valve connected in said system between
the storage tank and the one-way valve and in said flow path to
maintain said pressure level in said storage tank in the event
internal pressure in said storage tank rises independently of the
gas under pressure supplied thereto and a microbiological filter
connected in said flow path downstream of said pressure-maintaining
valve and between it and said storage tank.
2. In combination, a storage tank for storing spoilable contents
therein in a gaseous atmosphere; a system having means defining a
single flow path externally of the storage tank for supplying and
maintaining an aseptic gaseous atmosphere in said storage tank
comprising aseptic valve means in said single flow path for
supplying an inert aseptic gas into said storage tank, a
microbiological filter upstream of said aseptic valve in the same
single flow path for said gas as said aseptic valve, a conduit
defining a part of said flow path for supplying said inert aseptic
gas through said microbiological filter, a container externally of
the tank for containing said inert aseptic gas under pressure,
adjustable pressure-reducing valve means connected in said single
flow path to said container and said conduit for receiving gas from
said container and reducing the pressure to a pressure level to be
maintained in said storage tank, a one-way valve in said conduit
and single flow path downstream of the pressure-reducing relative
to said container for allowing flow of said gas in a direction to
said storage tank only, and a single pressure-maintaining valve
connected to said single flow path between the storage tank and the
one-way valve to maintain said pressure level in said storage tank
in the event pressure in said tank exceeds said pressure level in
dependence upon pressure rises arising internally of said storage
tank.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to storage of foodstuffs
and more particularly to a system or apparatus for supplying,
adjusting and maintaining an aseptic atmosphere and pressure in a
storage tank with a foodstuff as contents therein.
In the field of food processing, in which agricultural products are
process into foods, the products produced on a farm are not
immediately processed into their final form of processed foods
since they have season-dependent characteristics and are harvested
in large quantities at a time. The agricultural products are
partially processed and are stored in storage tanks or containers
in the form of half-processed products or primarily-processed
products and are then processed into final food products as they
are withdrawn from the storage container.
An example is tomatoes which have seasonal characteristics and are
harvested in large quantities at a time and are processed into
final food products such as tomato sauce, tomato ketchup or the
like, before final processing they are temporarily stored in the
form of a puree or paste, i.e. a primarily-processed product. These
primarily-processed food products are then processed into final
food products, such as tomato, sauce, tomato ketchup or the like as
the primary processed product is withdrawn from the temporary
storage container.
A most important thing in the series of steps of production of
processed foods is to store the primarily-processed product in a
perfectly sterilized state. Storing primarily-processed food
products in a large storage tank is the most effective and most
used method at present. However, when the primarily-processed food
products are stored in a large storage tank, the temperature
thereof must be kept as low as possible taking into account the
possibility of deterioration and viscosity resistance thereof. In
addition, much attention must be paid to the prevention of
microbiological contamination of these primarily-processed food
products. The contamination of supply and discharge pipes connected
to a large storage tank storing the primarily-processed food
products, contamination of a disc for restricting the supply and
discharge flows of the primarily-processed product, contamination
of the tank itself and its attachments or accessories, and the
entry or invasion of contaminating microorganisms, must be strictly
prohibited, even if such contamination is extremely small.
Various methods of and apparatus for storing primarily-processed
food products in an aseptic manner have been disclosed in, for
example, U.S. Pat. Nos. 3,871,824, 3,918,678, 3,918,942, 3,951,184
and 3,998,589 granted to Rechtsteiner.
For safety storing primarily-processed food products in an aseptic
manner in an aseptic storage tank, it is necessary to maintain a
positive pressure of aseptic gas in the storage tank. At the same
time, it is necessary to provide an anti-explosion safety device to
avoid an explosion resulting from an extraordinarily high internal
pressure which may result from accidental rot of the
primarily-processed food product in the tank.
According to the prior art, the aseptic gas is introduced into the
tank through a microbiological filter attached to the tank, so as
to maintain a positive pressure in the tank. A safety or relief
valve for anti-explosion purposes is attached to the tank
separately from the filter.
Taking into account that even slightly microbiological
contamination can finally grow to deteriorate the whole of the
contents of a storage system the number of parts, which may
constitute causes of contamination, must be reduced as great as
extent as possible. The known arrangements in which a
microbiological filter and a safety valve are installed separately
in the system increases the chances of contamination.
Particularly, specific attention must be paid in the known systems
to the sterilization and cleaning of the safety valve. The parts
around the safety valve directly attached to the tank require a
supply of sterilizer and cleaning agent.
It is of great importance to ensure microbiological cleanliness, in
order to store primarily-processed products for a long period of
time in an aseptic state.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus for adjusting the
internal pressure of an aseptic storage tank, in order to enhance
aseptic operation and maintenance of aseptic conditions of the
aseptic storage tank.
It is an object of the present invention to eliminate the
inconvenience caused by the aforementioned direct attaching of a
safety valve to the storage tank, by using a system in which
pressure-adjusting means are attached to the tank indirectly
through a microbiological filter which is directly attached to the
tank, and, at the same time, to make it possible to observe and
control the pressure and aseptic conditions in the storage tank
from externally of the latter.
It is another object of the invention to improve the preservation
of the quality of the primarily-processed food product, by
introducing an inert gas into the tank through a pressure-adjusting
system and the microbiological filter.
It is still another object of the invention to provide an apparatus
for adjusting the internal pressure of the aseptic storage tank
which can fulfill the above-stated two objects of the
invention.
Provision is made by the invention for a system externally of a
foodstuff storage tank for connecting a container of an inert
aseptic gas for supply of the gas to the storage tank through a
supply line having adjustable pressure-reducing valves. A one-way
valve in the supply line allows flow of gas only toward the storge
tank through a microbiological filter and an aseptic valve
connected in the supply line. Pressure in the tank is maintained at
the level set by responding to pressure rises in the supply line
due to pressure rises in the storage tank and relieving the
pressing upstream of the one-way valve by a pressure-maintaining
valve.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, as well as how these objects are achieved
will become clear from the following description of the preferred
embodiment taken in conjunction with the accompanying drawings in
which:
FIG. 1 is a perspective diagrammatic view of an aseptic storage
tank provided with a system according to the invention;
FIG. 2 is a diagram of a pressure-adjusting and maintaining system
according to the invention;
FIG. 3 is a perspective view of the storage tank in FIG. 1
illustrated in its working environment; and
FIG. 4 is a sectional view of an aseptic valve for carrying out the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the invention a foodstuff storage tank 12 is connected
to an aseptic valve 13 having a connection to a supply line for
supply of a primarily-processed food product into the storage tank
12, from a source such as arrangement 15, for temporary storage
therein. The tank is provided with an outlet aseptic valve 16 and
discharge connections 17 for delivery of the primarily-processed
food for final processing. The source of processed food product and
final processing arrangements have nothing to do with the system
and method according to the invention.
A second aseptic valve 20 is connected to the inlet aseptic valve
13 for supply of an inert aseptic gas under pressure into the
storage tank through the inlet aseptic valve 13 which is common
both to the inlet of foodstuffs into the storage tank or the inert
aseptic gas.
Provision is made, according to the invention, to supply an
atmosphere of an inert aseptic gas into the storage tank 12 and
maintain the tank at a selected internal pressure. A source of
inert septic gas under pressure such as a gas cylinder 23 is
provided. Control of the supply of gas is effected through an
apparatus or system 24 hereinafter described. The inert aseptic
gas, for example hydrogen, is supplied through a single line or
path 26 in which is connected a shut-off valve 28 and a
microbiological filter 30 connected to the inert gas septic valve
20.
A pressure gauge 32 is provided on the gas supply line to indicate
the pressure in the supply line 26 and in the storage tank 12. The
pressure in the tank as to the gas atmosphere therein is maintained
constant as later described; however, pressure in the tank can rise
due to break-down of the contents due to contamination.
Provision is made in the system for sterilizing the aseptic system
through a steam line connection 36 connected to the inert gas
supply line as shown.
According to the invention the system or apparatus 24 provided for
maintaining accurate control of the gas atmosphere provides for
adjustable control of the internal pressure of the tank. An
adjustable first pressure-reducing valve 38 is connected to the gas
cylinder 23 for making a coarse pressure reduction of gas supplied
to the supply line 26 from the gas cylinder. An adjustable second
pressure-reducing valve 40 is provided downstream of the first
pressure-reducing valve for making a fine adjustment of the gas
pressure to the storage tank. A pressure gauge 42 is provided
between the two pressure-reducing valves continuously indicating
the pressure. A valve 46 controls the application of gas pressure
to a second pressure gauge 48 indicating the gas pressure setting
in the supply line 26.
The gas system 24 is isolated from back pressure in the supply line
section between the gas supply system and the storage tank by a
one-way or check valve 50. The gas supply system 24 can be bled of
or drained through a drain valve 51. The check valve 50 allows gas
flow only in the direction of the storage tank. In isolating the
storage tank internal pressure from the gas supply system by the
check valve the invention makes it possible to maintain a
controlled internal pressure in the storage tank. Moreover,
provision can thus be made for responding to excess pressure in the
storage tank and relieving it without need of a relief valve
directly mounted on the storage tank. It is thus also possible for
the invention to provide a method of adjusting the internal
pressure of a storage tank for storing foodstuff material in an
aseptic manner.
In order to maintain a selected maximum internal pressure in the
storage tank a pressure-maintaining valve 52 is provided upstream
of the check valve 50 relative to the gas flow. This valve responds
to pressure in the storage tank and maintains it. In the event of a
build-up of pressure in the storage tank the pressure-maintaining
valve 52 functions in relieving of excess pressure.
The elimination of a relief valve on the storage tank eliminates
possibilities of contamination usually present in storage tanks
that have relief valves directly mounted thereon. Moreover,
cleaning fluids therefor are also eliminated.
When it is desired to maintain the internal pressure of the aseptic
storage tank 12 at a positive pressure of, for example 0.45
kg./cm..sup.2 to 0.50 kg./cm..sup.2, the pressure maintaining valve
52 is adjusted to 0.50 kg./cm..sup.2, while the finely adjustable
reducing valve 40 is adjusted to reduce the pressure down to 0.45
kg./cm..sup.2.
As a result, the aseptic inert gas is supplied into the aseptic
storage tank, through the finely adjustable reducing valve 40,
check valve 50 and the microbiological filter 30, when the internal
pressure in the aseptic storage tank comes down below 0.45
kg./cm..sup.2.
When the internal pressure is maintained between 0.45 kg./cm..sup.2
and 0.50 kg./cm..sup.2, the check valve and the pressure preserving
valve 52 are not operated so that the internal pressure is
maintained.
On the contrary, if the internal pressure in the storage tank 12
has become higher than 0.50 kg./cm..sup.2, the internal pressure is
relieved through the microbiological filter and the pressure
maintaining valve.
It is therefore possible to maintain the atmosphere of the aseptic
gas of the desired positive pressure in the aseptic storage tank,
through suitably adjusting the valves from the outside of the
tank.
The aseptic valves according to the invention comprise a valve body
50 to which is secured a bonnet 53 by a connector or clamp 54 and
have a recess 55 within which is disposed a bushing 56 snugly
fitting therein. The bushing is made of a molded fluoric resin, for
example; and held by a plug 57 so that the valve can be readily
disassembled for cleaning. A valve stem 59 extends axially through
the bushing and bonnet and is provided with a valve element or disc
61 which seats on a seat 63 and is operable by a manual actuator
64.
The aseptic valve is maintained sterilized by a constant supply of
a sterilizing liquid flowing through a first cavity or chamber 65
which is formed by an annular recess in the bonnet and the valve
body. The sterilizing liquid enters at an inlet 67 and is
discharged through an outlet 69.
The bushing has an annular circumferential recess that forms with
the bushing recess 55 a second sterilization chamber 72 and a bore
with a major diameter that forms with the valve stem 59 a third
sterilization chamber 75 in communication with the second chamber
through a passageway, not shown, in the bushing. A sterilizing
liquid is continuously replaced through an inlet 78 and flows out
an outlet 79, so that the valve stem is constantly bathed in a
sterilizing liquid to prevent micro-organisms from entering the
storage tank through the valve stem and other parts of the
valve.
In order to maintain a fluidtight seal the valve is provided with a
plurality of O-ring seals 81,82,83,84,85 disposed as shown so that
the valve is completely sealed. The valve connections are
constructed as shown at 90,91 and in broken lines 92 depending on
where and how the aseptic valve is to be connected.
Those skilled in the art will understand that the system and
aseptic valve construction described reduce possibilities of
bacterial or microbiological contamination and maintain the storage
tank at a safe internal pressure. The valve parts in contact with
the sterilization fluid are preferably constructed of anticorrosive
materials.
It is possible to maintain an aseptic gas atmosphere of a positive
pressure in the aseptic storage tank and to protect the tank
against explosion, as well as to observe and control the condition
in the aseptic tank from the outside of the latter, by making use
of the pressure adjusting means connected to the aseptic storage
tank through the microbiological filter.
* * * * *